This application to continue as the Statistical and Data Management Center (SDMC) for the HIV Prevention Trials Network (HPTN) is one of three applications comprising the Leadership Group of the HPTN. The HPTN scientific agenda focuses exclusively on RFA priority number 6: "Prevention of HIV Infection." This application describes how the Statistical Center for HIV/AIDS Research & Prevention (SCHARP) will achieve the aims of the RFA to (1) provide statistical leadership for the design, conduct, analysis and publication of Network clinical trials/studies; (2) provide central data management capability that includes randomization, data set and case report form design, central storage, security, processing and retrieval of study results; (3) provide data management and protocol training throughout the Network; (4) provide data- focused clinical trials implementation, and operation; and (5) contribute to cross-Network efforts in developing common data elements and data interfaces. SCHARP has extensive experience in the design, conduct and analysis of global HIV vaccine and prevention studies. Thus, the systems we propose to use for data collection, managment, monitoring, and analysis are all well tested and in accordance with ICH guidelines. SCHARP statisticians will also develop and deploy novel statistical methodologies to increase the efficiency and rigor of the proposed program of HIV prevention trials. The HIV/AIDS epidemic continues to expand in almost all regions of the world, with approximately 4.8 million new infections in 2003 (UNAIDS 2004 Report on the Global AIDS Epidemic). Although finding a vaccine to protect against infection and/or disease progression is a public-health priority, it is recognized that this goal may be years away. Therefore, the need for finding other types of effective prevention measures is critical. Only through clinical trials held to the highest scientific and regulatory standards will this goal be achieved.